1. Field of the Invention
The present invention relates to an electrical control unit.
2. Description of Related Art
Electrical control units such as shown in FIG. 5 and FIG. 6 are mass-produced for vehicles. In the unit shown in FIG. 5, a substrate 102 that mounts electronic components 101 is fixed by bonding on a plane plate 100 manufactured by aluminum. Large-size electronic components 104 (such as coils and capacitors), which cannot be mounted on the substrate 102, are held and fixed on a resinous frame 103 that combines a case and a connector. Bus bar (metallic electrical conductor) 105 is inserted into the resinous frame 103. The large-size electronic components 104 are electrically connected to a connective land of the substrate 102 via a lead wire 106, the bus bar 105, and a ribbon wire (metallic foil) 107. The bus bar 105, which is inserted into the resinous frame 103, is used as a conjunctive pin (connector pin) of a connector 108. This unit is mounted on an engine 200.
In the unit shown in FIG. 6, an aluminum case 110 is formed in a box-style, a substrate 111 is fixed by bonding in the aluminum case 110, and all electronic components 112, 113 are soldered on the substrate 111. A connector 114 is fixed to the aluminum case 110, and the aluminum case 110 is fixed on an engine (a vehicle) 200 by using a brim 115 of the aluminum case 110. The aluminum case 110 functions as a heat sink. Thus, most of heat from the electronic components 112, 113 disposed on the substrate 111 is conducted to the aluminum case 110, and the heat is radiated to the engine via the brim 115. A part of the heat is conducted to the case 110 by a radiation and a transmission by the air inside the case 110, and is radiated from the case 110 to the air.
The unit of FIG. 5 can include the large-size electronic components 104, which produce large outputs, in the case. As a result, the unit of FIG. 5 can be used for producing large outputs, such as an injector driver for a diesel engine, and an injector driver for a direct gasoline-injection engine. However, the plane plate 100 and the resinous frame 103 constitute the case, the connector 108, and a support member for the large electronic components, and the bus bar 105 has an outside jutted structure to be used as the connector pin. As a result, width of the bus bar becomes width of the connector pin, and consequently the number of the connector pins is limited (for example, approximately 20 pins).
Recently, the number of the input and output terminals of the electronic control units is increased significantly (for example, 50 pins to 150 pins), and thus the structure of FIG. 5 cannot meet the increase of the terminals physically. As a result, the electronic control units are divided into a unit for a large output and another unit for a small output (control unit). In addition, various kinds of the connector 108 are used. If the shape of the connector is changed as necessary, variations of the case are increased, and consequently this causes a problem that the variations drive up costs for the electronic control units.
On the other hand, the unit of FIG. 6 is limited to use for the small output device (control element). The connector 114 has a capability of a number of the input and output terminals up to around 100 pins to 150 pins by multipurpose small clearance design. However, it is difficult for the structure to install the large-size electronic components 104 as shown in FIG. 5. Even if the substrate 111 included in the aluminum case 110 is a large size, the electronic components may be broken away from the substrate due to an applied vibration and weight of the electronic components itself under a condition that the electronic control units for an internal combustion engine is installed directly to the engine.